Max Planck Institute for Polymer Research (MPI-P) scientists have managed to develop a single layer OLED which they say can be created with an inkjet printer
According to the scientists, the newly developed prototype stands toe to toe with current, commercially available OLEDs in terms of luminosity and efficiency.
Organic light-emitting diodes (OLEDs) no longer consist of compounds containing the semiconducting material gallium. They instead use carbon as their main component.
Though they offer a greener alternative to conventional light-emitting diodes, the luminosity and lifetime of present-day OLEDs are currently lower than LEDs.
In order to remedy this, MPI-P scientists led by group leader Gert-Jan Wetzelaer have developed a new OLED concept consisting of a single layer that is supplied with electricity via two electrodes.
Unlike current OLEDs which consist of various wafer-thin layers, the new prototype simplifies the production process and paves the way for printable displays.
With their first prototype, the Mainz scientists were able to show that they can generate a brightness of the emitted light of 10,000 candela/square meter with a voltage of only 2.9 volts.
According to the scientists, this corresponds to about 100 times the luminosity of modern screens.
The device’s external efficiency stands at 19%; this means that 19% of the electrical energy supplied is converted into light that comes out in direction of the viewer.
The researchers were also able to measure a so-called LT50 lifetime of almost 2000 hours at a brightness equivalent to ten times that of modern displays in continuous operations.
The scientists made use of a light-emitting layer based on so-called ‘Thermally Activated Delayed Fluorescence’ (TADF).
TADF-based OLEDs do not require expensive molecular complexes containing rare-earth metals that are being used in current OLEDs.